Combobox queryMode: 'remote'

Hi, this is my first post. I'm from Brasil.
I'm trying to use a combobox with queryMode: 'remote'.
It was worked until I removed this: <script type="text/javascript" src="../../libs/extjs/bootstrap.js"></script>

If I use <script type="text/javascript" src="../../libs/extjs/ext-all-debug.js"></script>
it's work!
but if I use <script type="text/javascript" src="../../libs/extjs/ext-all.js"></script>
it's don't work too!

however, if I use <script type="text/javascript" src="../../libs/extjs/ext-all-debug.js"></script>
combobox works but all forms submit in my application don't work.
the following error occur :this.up("form") is undefined